Reverse the string without using any temporary variable?

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1. We can use XOR logic for swapping the variables.

 public String reverseString(String str)
{
      char[] a = str.toCharArray();
      int len = a.length-1;
      int half = a.length/2;
   
      for (int i = 0; i < half; i++) 
      {
            a[i] ^= a[len - i];
            a[len - i] ^= a[i];
            a[i] ^= a[len - i];
       } 

       return String.valueOf(a);
}

 2. Using built-in reverse() method of the StringBuilder class.
    public void reverseString(String input)
    {
        StringBuilder input1 = new StringBuilder();

        // append a string into StringBuilder input1
        input1.append(input);

        // reverse StringBuilder input1
        input1 = input1.reverse();

        // print reversed String
        for (int i=0; i<input1.length(); i++)
            System.out.print(input1.charAt(i));

    }

          

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